Ming lives in Seattle and recently bought a $375 ticket to attend a Seattle Seahawks game. He is a huge fan, so even though the ticket is pricey it is well below his willingness to pay of $600. However, as game day approaches, Ming receives an invitation from his friend, Cassandra, to spend the day at the Museum of Pop Culture touring a big exhibit on Marvel superheroes. The museum visit would only cost $75, but Ming (being a big Marvel fan too) would be willing to pay $250. What is his opportunity cost of going to the museum?